The document outlines a lab exercise focused on plant-based proteins and their dietary quality, emphasizing the calculation of protein needs and cost per gram of protein from various food sources. It includes detailed tables for determining costs, amino acid content, and evaluating protein sources based on completeness and essential amino acids. Additionally, it addresses the importance of combining incomplete proteins in vegetarian diets and explores methods for calculating individual protein needs.

1. LAB 3 PLANT BASED PROTEINS AND DIET QUALITY
LAB 5
Protein Foods and Calculating Needs
Enter Your Name Here:
Fill out Tables 1-5 to successfully complete this exercise and
answer all questions. Save your report as a pdf file labeled
Protein [your initials]. Submit via the turnitin link in the Lab 3
folder.
Calculating the Cost of a Gram of Protein
Complete Table 1 by determining the cost per gram of protein
for each item. Why calculate cost per gram rather than per
serving? A per gram value allows you to compare data across all
sources without worrying about the effects of different serving
amounts for each item. Once you have the cost per gram you
can rate the foods from highest to lowest based on cost. Some of
the foods listed below are complete proteins (milk, cod, tofu,
and egg) while others are not.
COMPLETE THE FOLLOWING TABLE! CALCULATE THE
COST PER GRAM! USE THE SERVING SIZES THAT ARE
GIVEN. CALCULATE MILK USING 1 CUP AND COD
FILLET USING 3 OUNCES.
Table 1 Computing the Cost of Dietary Protein
Source
Serving size
Protein (g)/serving
Cost/serving
Cost/gram protein
Milk (cow)
1 cup
8 g

2. $0.22
Pinto beans
½ cup
10 g
$0.20
Cod fillet
3 ounces
19 g
$3.00
Soymilk
1 cup
8 g
$0.26
Tofu
½ cup
10 g
$0.18
Egg
1 large
6 g
$0.25
Peanut butter
2 Tbsp.
8 g
$0.12
Chia seeds
1 ounce
5 g
$0.70

3. Rice cooked
½ cup
2 g
$0.24
Calculating cost per gram of protein in 1 cup of milk
1. Determine the price of one cup. To determine the cost of 1
cup of milk divide the cost of a gallon of milk by 16 (there are
16 cups in a gallon). If milk costs $3.50/gallon than the cost of
1 cup is $3.50/16 cups or $0.219 which rounds up to $0.22 per
cup.
2. Determine the cost of a gram of protein. One cup of milk
contains approximately 8 grams of protein. Divide the cost of
one cup of milk by 8 to calculate the cost per gram. One cup
costs $0.22 so 1 gram costs $0.22/8 grams or $0.0275 rounded
to $0.03/gram of protein.
Rounding rules: If the trailing digit of a number is less than 5
round down. For example: the number 15.34 is rounded down to
15.3. If the trailing digit is 5 or greater round up. For example,
the number 15.56 is rounded up to 15.6. Round US money
(dollars) to the second decimal place or penny.
Placing a zero before a decimal: If a number is less than 1,
place a zero (0) before the decimal point. For example, $.25 is
written as $0.25. This notation draws attention to the decimal
point and avoids mistaking the number as the integer 25.
Table 2 Order the Following Foods by Cost per Gram of Protein
(Most to Least Expensive)
Use the information in Table 1 to answer this question. Not all

4. items from Table 1 are listed.
COMPLETE THE FOLLOWING TABLE BY PUTTING FOODS
FROM TABLE 1 IN THE CORRECT ORDER!
List the following foods in order from most expensive (greatest
cost per gram of protein) to least.
Milk, pinto beans, cod fillet, egg, chia seeds, and rice cooked
Order
Food Item
1
Most Expensive
2
3
4
5
6
Least Expensive
Exploring Amino Acid Content of Representative Foods
The following table lists the amino acid content of a variety of
food sources including animal (cow milk, egg), seafood (cod),

5. legume (pinto beans, soymilk, tofu, peanut), seed (chia) and
grain (rice).
Table 3 Protein Foods with Selected Amino Acid Content
Item
Serving Size
Lysine
Methionine
Arginine
Tryptophan
Milk (cow)
1 cup
0.644
0.203
0.220
0.098
Pinto beans
½ cup
0.618
0.118
0.500
0.108
Cod fillet
3 ounces
1.782
0.575
1.161
0.218
Soymilk
1 cup
0.040
0.008
0.057
0.012
Tofu
½ cup

6. 0.582
0.139
0.580
0.100
Egg
1 large
0.456
0.190
0.410
0.083
Peanut butter
2 Tbsp.
0.215
0.084
0.874
0.073
Chia seeds
1 ounce
0.275
0.167
0.608
0.124
Rice, cooked
½ cup
0.080
0.052
0.184
0.026
COMPLETE THE FOLLOWING TABLE BY EVALUATING
THE AMINO ACID CONTENT OF FOODS IN TABL3 3!
Table 4 Evaluating the Amino Acid Content of Foods
QUESTION
YOUR ANSWER
What is the lysine content of milk?

7. Which food is the richest source of lysine?
What is the methionine content of soymilk
Which plant food is the richest source of arginine?
Which plant food is the richest source of tryptophan?
Calculating Kyle’s Protein Needs Based on Physical Measures
& Estimates
Calculate Kyle’s daily protein needs using the three methods
listed below. Enter results in Table 5. Round your answers to
the nearest whole number.
1. University of Maryland Medical System Protein Calculator
http://www.healthcalculators.org/calculators/protein.asp
2. World Health Organization Recommendations
3. Calculate Protein Needs Based on Percent of Daily Calories
COMPLETE TABLE 5 BY USING KYLE’S FACTS AND
COMPLETING THE STEPS IN “METHODS” BELOW. BE
SURE TO FILL IN THE BLANKS IN STEP 2 AND 3 OF
METHODS.
Kyle’s Facts
a. 26 years old
b. Male
c. 155 pounds
d. 5 feet 10 inches tall
e. Medium frame
f. Sedentary
Complete the calculations:
1. Find the link to the University of Maryland Medical System
Protein Calculator here:
http://www.healthcalculators.org/calculators/protein.asp Enter

8. Kyle’s facts (above) and report his estimated protein needs in
Table 5.
2. The World Health Organization recommends 0.75 (0.8) grams
of protein per kilogram of body weight for non-obese adults of
both genders when the biological value of the protein is similar
to that of milk or egg.
http://www.fao.org/docrep/003/aa040e/AA040E09.htm#ch8.
To calculate protein needs convert weight in pounds to
kilograms and multiply results by 0.8 . Round your answer to
the nearest whole number and report it in Table 5.
Subject
Weight (Lb.)
÷ 2.2 lb./kg
X
Protein (g)
26 year-old male
155
0.8
3. Percent of Daily Calories MyDietAnalysis estimates Kyle’s
daily caloric needs as 1360 calories. Use the chart below to
calculate his projected protein needs. Report results in Table 5.
Calories in Diet
(20% of Calories)
Protein Calories
Calories/gram
Protein (g)
1360
X 0.20
÷ 4

9. REPORT THE DATA
Table 5 Estimates of Kyle’s Daily Protein Needs by Different
Methods
Estimate Source
Protein Needs in Grams
UMMS Protein Calculator
World Health Organization
Percent of Daily Calories
3
LAB 3 PLANT BASED PROTEINS AND DIET QUALITY
LAB 5
Plant Based Diets and Calculating Protein Needs
What are Proteins?
Proteins are complex molecules that exhibit a four-stage
structural hierarchy and three-dimensional folding. This
complexity gives each molecule its unique shape and function.
In the primary structure, different amino acids in each amino
acid chain of a protein molecule interact laying the foundation
for molecular folding and a unique three-dimensional shape. In
the secondary structure hydrogen bonding between neighboring
amine groups and carboxyl groups of a protein molecule creates
folding. The tertiary structure is a stable secondary structure of
an amino acid chain, or polypeptide, with its folds and
conformations. A quaternary structure occurs in when there are

10. multiple polypeptide chains that interact in a macromolecule.
This all adds up to biologically active molecules that are
structural (muscle, connective tissue, hair), catalysts of
chemical reactions (enzymes), and regulator agents (hormones),
blood components, cellular messengers, and antibodies.
Protein Composition
An amino acid is a carbon with four bonds: to an amino group, a
carboxyl group, a hydrogen atom and a side chain [R])
A protein is one or more linked peptide molecule
containing amino acids
A protein typically contains 100-600 linked amino acids
(there are 51 amino acids in insulin)
Nomenclature
Dipeptide 2 linked amino acids
Oligopeptide 3-8 linked amino acids
Polypeptide 9 or more linked amino acids
Structure
Primary Order of the amino acids in the chain
Secondary Two-dimensional structure due to hydrogen
bonding
Tertiary Three dimensional folding of a protein due
to interaction of amino acids
Quaternary Association of polypeptides into a
functioning protein
Denaturation
Loss of secondary, tertiary and/or quaternary structure
Loss of function rendering the molecule biologically
inactive
Destruction of hydrogen bonds caused by temperature, pH,
mechanical agitation, salts

11. Essential amino acids There are nine amino acids that humans
are unable to manufacture or cannot do so in sufficient
quantities to support protein synthesis. The nine essential or
non-dispensable amino acids are histidine, isoleucine, leucine,
lysine, methionine, phenylalanine, threonine, tryptophan, and
valine. There are four non-essential or dispensable amino acids
that the human body can produce using carbohydrate and
nitrogen if food does not provide them. The non-essential amino
acids are alanine, asparagine, aspartic acid, and glutamic acid.
There are seven conditionally essential amino acids that only
are essential at specific stages of life, such as infancy, or when
there is stress, illness, or injury. The conditionally essential
amino acids are arginine, cysteine, glutamine, glycine, proline,
serine, and tyrosine. Under normal circumstances body is able
to manufacture non-essential amino acids from other available
amino acids. As long as there is adequate protein in the diet
acquiring non-essential amino acids is not an issue.
Table 1 Amino Acids Found in the Human Body
Essential (9)
Non-Essential (4)
Conditionally Essential (7)
Histidine
Alanine
Arginine
Isoleucine
Asparagine
Cysteine
Leucine
Aspartic acid
Glutamine
Lysine
Glutamic acid
Glycine
Methionine

12. Proline
Phenylalanine
Serine
Threonine
Tyrosine
Tryptophan
Valine
Source: MedlinePlus: A Service of the US Library of Medicine
http://www.nlm.nih.gov/medlineplus/ency/article/002222.htm
Why Is Amino Acid Classification in Table 1 Different from
that in the Textbook?
Table 1 replicates the amino acid classification of the National
Institute of Medicine/National Institute of Health and is more
sensitive to health states that affect the body’s ability to
synthesize or manufacture, conditionally essential amino acids.
The textbook simplifies the organization by providing only two
groups: essential/non-essential. The authors classify cysteine,
glutamine, glycine, proline, serine, and tyrosine as non-
essential and arginine as essential. Arginine is recognized as
essential during infancy and thought to benefit wound healing,
thus its classification by the National Institute of Medicine as
conditionally essential.
What Should You Conclude about the Discrepancy?
First and foremost you should realize that nutrition is a complex
subject! Secondly, recognize that although most sources agree
that protein in the human body is comprised of 20 amino acids,

13. not all agree on how to classify those amino acids. Why is this
relevant? Scientific knowledge continues to evolve as
experiments are replicated and observations are refined to more
clearly describe natural phenomenon. Protein supplements are a
hotly advertised and prescribed group of substances.
Understanding that our knowledge of protein function is
incomplete gives you pause to decode market messages and
make informed decisions. Track the science on conditionally
essential amino acids and investigate their place in health
messages and product sales.
Complete and Incomplete Proteins Not all protein foods are
created equal and some provide more essential amino acids than
others. Milk and eggs are sometimes called the protein gold
standard in that their amino acid profile closely matches that
needed for building body tissues. Most meat-food from seafood
and animal sources provide complete proteins. Complete
proteins contain all the essential amino acids in quantities that
allow protein synthesis, or building, to take place. Soybean is
the only plant food recognized as providing a complete protein.
All other plant sources must be consumed in combinations that
complement each other so that those that are low in a given
amino acid, such as lysine, are combined with others that are
high in that limited amino acid. Consuming complementary
protein foods over the period of a day adequately supports
protein synthesis.
Vegetarianism A vegetarian is someone living on a diet of
grains, pulses, nuts, seeds, vegetables, and fruits with or
without the use of dairy products and eggs. A vegetarian does
not eat any meat, poultry, game, fish, shellfish or crustacean, or
slaughter by products such as gelatin or animal fats. A
vegetarian must obtain protein from plant foods, specifically,
grains, legumes, nuts, seeds, and vegetables.

14. Rule of Thumb Generally speaking grains complement legumes
as well as nuts and seeds. In a vegetarian diet, to have an
adequate daily protein intake it’s advisable to include all types
(grains, seeds, legumes and vegetables) of plant foods each day.
Grains Cereal grains include wheat, rice, corn, oats, barley, rye,
millet, sorghum, buckwheat, and quinoa. In terms of worldwide
utilization rates, wheat, rice and corn comprise over 85% of
grains consumed by humans. Grains tend to be lacking in lysine
while legumes are low in methionine. Combining grains and
legumes provides a more complete protein than either does
alone.
Legumes An important source of plant protein is found in the
legume family. The term legume refers to either the plant itself
or its edible portion such as the fruit or pod. The French word
légume translates as vegetable, and most people place familiar
legumes, such as pinto beans and black-eyed peas, in the
vegetable food group. Legumes are chameleons though and
when called upon can substitute for meats as their considerable
protein content allows them to join the meats as meat-alternates.
Legumes include beans, lentils, peas, peanuts, and soybeans that
are sources of both foods and oils.
A legume is a simple dry fruit that opens along a seam on two
sides. A common name for this type of fruit is a pod, although
this term is sometimes applied to other fruits such as a pepper
pod. Well-known plants that are legumes include clover, peas,
beans, and peanuts. Peanuts are not nuts in the botanical sense.
A peanut is a legume that does not spontaneously split open
along a seam. Legume seed and foliage has comparatively
higher protein content than non-legume plant foods. Due to an
ability to fix atmospheric nitrogen legumes contain significant
amounts that are important to protein synthesis.
Sources of Arginine a Conditionally Essential Amino Acid

15. Walnuts, filberts (hazelnuts), pecans, Brazil nuts, sesame and
sunflower seeds, brown rice, raisins, coconut, gelatin,
buckwheat, almonds, barley, cashews, cereals, chicken,
chocolate, corn, dairy products, meats, oats, and peanuts are
sources of arginine a conditionally essential amino acid.
Vegetarian Food Guide Pyramid
Source: National Center for Nutrition and Dietetics
The American Dietetic Association; Based on the USDA Food
Guide Pyramid
Investigating Protein Foods
Consider all the foods that you eat. Which ones are good
sources of complete proteins? Which ones are poor sources?
What criterion did you use to classify each as a good, fair or
poor source? Did you assume that any food from the meat group
is a good source while any from the grain group is a poor
source?
Review the vegetarian food guide pyramid. Note that there is a
box or group for dry beans (legumes), nuts, seeds, eggs and
meat substitutes. This diverse group is a major source of protein
in a vegetarian diet however, with the exception of soybean, the
protein of each item is incomplete. Milk and dairy foods
provide high quality protein yet in some vegetarian diets these
animal sourced foods are not consumed. Some vegetables
provide substantial amounts of incomplete proteins while most
fruits have negligible amounts of protein. Surprisingly, a
medium baked potato has 3 grams of protein, however, the
quality is poor due to meager amounts of essential amino acids
such as methionine and tryptophan. Grains such as rice, wheat,
and corn provide incomplete proteins that must be

16. complemented by the dry bean, nut, seed and egg or the dairy
group. This complementation, or combining of incomplete
protein sources to make a complete protein improves protein
quality making it possible to meet daily needs for protein
synthesis and body maintenance.
Calculating the Cost of a Gram of Protein
Complete Table 4 by determining the cost per gram of protein
for some common foods. Why calculate cost per gram rather
than per serving? A per gram value allows you to consistently
compare data across all sources. Once you have the cost per
gram you can rate the foods from highest to lowest cost and
compare whole foods to protein supplements.
Table 2 Computing the Cost of Dietary Protein
Source
Serving size (g)
Protein (g)/serving
Cost/serving
Cost/gram protein
Milk (cow)
1 cup
8 g
$0.22
$0.03
Pinto beans
½ cup
10 g
$0.20
$0.02
Cod fillet
3 ounces
19 g
$3.00
$0.16
Soymilk

17. 1 cup
8 g
$0.26
$0.03
Egg
1 large
6 g
$0.25
$0.04
Peanut butter
2 Tbsp.
8 g
$0.12
$0.02
Calculating cost per gram of protein in 1 cup of milk
1. Determine the price of one cup. To determine the cost of 1
cup of milk divide the cost of a gallon by 16 (there are 16 cups
in a gallon).
If milk costs $1.85/gallon than the cost of 1 cup = $1.85/16
cups or $0.116 rounded to $0.12 per cup.
2. Determine the cost of a gram of protein. One cup of milk
contains approximately 8 grams of protein. Divide the cost of
one cup of milk by 8 to calculate the cost per gram
One cup costs $0.22 so 1 gram costs $0.22/8 grams or $0.0275
rounded to $0.03/gram of protein.
Calculating Protein Needs Based on Physical Measures
The online protein calculator linked below bases estimates
protein needs on height, age, gender, body frame, and activity
level. Why do you think that it does not include weight? What is
the effect of age or gender on protein needs? How does activity
level change needs?
University of Maryland Medical System Protein Calculator

18. http://www.healthcalculators.org/calculators/protein.asp
World Health Organization Recommendations
The World Health Organization recommends 0.75 (0.8) grams of
protein per kilogram of body weight for non-obese adults of
both genders when the biological value of the protein is similar
to that of milk or egg.
http://www.fao.org/docrep/003/aa040e/AA040E09.htm#ch8.
Table 3 Calculate Protein Needs Based on Weight
To calculate protein needs convert weight in pounds to
kilograms and multiplying result by 0.8 grams.
Subject
Weight (Lb.)
÷ 2.2 lb./kg
X (factor) g/kg
Protein (g)
30 year- old man
185
84 kg
0.8
67 g
10 year-old boy
80
36 kg
0.8
29 g
50 year-old woman
145
66 kg
0.8
53 g
16 year-old girl
110
50 kg
0.8

19. 40 g
You
0.8
Table 4 Calculate protein needs based on percent of daily
calories
Calories in Diet
(20% of Calories)
Protein Calories
Calories/gram
Protein (g)
1500
X .20
300 calories
÷ 4
75 g
2000
X .20
400 calories
÷ 4
100 g
2500
X .20
500 calories
÷ 4
125 g
3000
X .20
600 calories
÷ 4
150 g

20. 5